Causal Nexus
by Bearit
Summary: Adversity sparks something unexpected between a marine and an engineer. Tali/Kal


_**Notes**: Special thanks to Freesourceful and bananacave for the betas!_

* * *

Kal'Reegar knows that if he dies, he will die for the Migrant Fleet.

He has a puncture in his suit and he stands alone against a platoon of geth and an annoyingly persistent colossus, but as long as he has air in his lungs and rockets to launch he will fight. Too much is at stake, and he knows as much even without Tali'Zorah telling him about the research she is doing. If anyone is to return to the Flotilla, it must be Tali'Zorah. His mission objectives are clear.

For the Fleet, Tali'Zorah must survive.

He loads another rocket, and he ducks out of cover long enough to aim at the colossus and fires. He drops behind the wall as the colossus retaliates. He will be damned if he fails at his mission. He will be damned if he falls before Commander Shepard and her team arrive.

He needs to make sure Tali is safe before he dies.

For the Fleet.

* * *

"Please, do what you can to keep Reegar alive."

As Shepard's face vanishes from the screen, Tali mentally kicks herself. Keep Reegar _and his men_ alive, she's supposed to say. Not just Reegar. But Shepard is not the type to dwell on these types of details, and she will keep as many alive as possible because she doesn't know how to do any differently. Still, Tali worries, and she throws herself back into her work in part to make sure she finishes before it is over one way or another.

Between the numbers and data points, she finds that she cannot help but to remember the team's first night on Haestrom, when Kal'Reegar sent a couple of his men on watch and the others retired for the night. Tali continued to work, and Reegar suggested that she get some shut-eye. She promised she would after the download, and after a brief pause, Reegar asked her what she was doing.

At first, Tali was unsure of what to say. She briefed Kal'Reegar and his men on the nature of Haestrom's sun, that their shields will be largely ineffective, and that they should limit their exposure to the sun and that they should do so if and only if necessary. That was all the marines needed to know to do their job, and no one pressed her with more questions than that at the time.

But then there was Kal'Reegar, asking her about her work, so she responded as simply and briefly as she could about the data she was collecting.

Without missing a beat, Reegar asked, "Do you have any idea what might be causing it?"

Tali did not expect him to continue the conversation. "I'm not sure. I mean, that is what this research is going to tell us, but if I had to guess, it might be dark energy."

"That doesn't sound good, ma'am."

"No, it doesn't." There was a brief pause. And then, "Why do you ask, Reegar?"

"Just curious, ma'am."

Tali shakes herself out of the memory. Now is not the time to think about this. The fighting is dying down outside and she needs to finish the upload. With any luck, Shepard is finally here, and Kal'Reegar is still alive... and his men.

The digital chatter of the geth dies with gunfire and the welcome high-pitched whir of shutdown reaches Tali's ears, and she unlocks the door. At first, she is thrilled to see Shepard and relieved that she has Garrus in tow. But her heart sinks when only one other person joins Shepard's side, and it is one of the Cerberus humans Shepard had with her on Freedom's Progress. Tali turns back to the console and realizes that her greeting to Shepard is cold, and for once she is thankful for her mask: no one can see how exactly how upset she is at the loss of her entire team.

* * *

Kal'Reegar spends a week in the med bay back on the Flotilla. His wound heals but with an infection that gives the doctors some cause for worry. He has given his report about what happened on Haestrom, and Admiral Rael'Zorah himself visited once to hear the details of his daughter's decision.

Kal still has no idea what Tali'Zorah's new mission is, but he knows that it must be important enough to request a transfer, for Tali'Zorah is willing to follow Shepard anywhere in the galaxy and beyond. Based on what he has heard and the few stories Tali told him on Haestrom--she never hid her undying admiration for the human--he decides that it is better if he doesn't know what she is up to. Less cause for worry. Besides, while on her Pilgrimage she played a pivotal role in the Battle of the Citadel at Shepard's side. Tali'Zorah could take care of herself, and Shepard is more than qualified to see to her safety as well.

He also spends his time in the med bay going over what happened on Haestrom, the decisions he made, and the name and uniform of each marine that fell to the geth. He remembers Shepard's voice over the comm ("You're willing to throw your life away for research?") and Tali'Zorah's reaction to the casualties ("This damn data better be worth it."), and he gets the sinking feeling that his mission is not over yet.

After he is released, Kal visits the scientists every other day to see what results they uncover. The scientists give him puzzled glances every time he walks into their lab, but they make no move to kick him out and often they are just happy that a regular grunt is legitimately curious about their work. The scientists seem to understand that he is here because he lost his entire squad and he wants to know the meaning behind their deaths. They are the most helpful of the bunch, explaining to him in layman's terms what they are finding.

With each visit, the researchers grow more confident in Kal's knowledge of the data, and they begin throwing terms at him that fly right over his head. He nods along, trying to piece together the jargon he knows. He soon finds that if he connects their words to Tali'Zorah's theories, he understands them a lot easier. Slipping into those memories quickly becomes habit when he visits the scientists.

One day, while one of the older scientists is talking tech to him, Kal finds himself remembering not what Tali'Zorah said about the research and not the images of geth firing mercilessly at his squad. Instead, he remembers the quiet moments, when he would duck between buildings to keep his shields and weapons from overheating, keeping an eye on Tali'Zorah with every step he took. He remembers staying at her back when the entire team was on the move from one part of the complex to another, not feeling comfortable if he had to turn away from her for one second. Mostly, he remembers the nights when he stayed up with Tali as she worked. Sometimes they would talk, and not always about the research; other times, Kal would remain silent as he waited for Tali to work herself to sleep.

This is when he realizes he is past learning the meaning of his squad's death, and he finds that visiting the scientists is now the one thing that keeps him connected to Tali. He doesn't know why, but it is not a connection he is willing to lose.

* * *

Adrenaline pumps through Tali as she rushes to keep up with Shepard, ducking under cover and shooting at the Collectors as they swarm the escape route that damn AI has sent them on. Tali is not convinced that the AI isn't doing this on purpose, especially after discovering that Cerberus has knowingly sent Shepard and her team into a trap, but she knows she has little choice but to trust it. Shepard does, somehow; Tali could not presume to do otherwise, not when her only other option is to wander the Collector Ship aimlessly until the Normandy is destroyed again.

They come to the upper level of a small room, two ramps leading down, and the AI instructs them to head for the open door on the far side. Before they reach the door, it slams shut, and Garrus hisses, "Praetorian!"

Shepard commands both to take cover, and as Tali ducks behind the ramp she just ran down, she sees a floating, four-limbed creature that glows of thirty deformed husks looming towards them. Shepard takes the giant missile launcher off her back, and behind the other ramp Garrus is carefully aiming with his sniper rifle. Tali readies her combat drone. She cannot see their faces through their helmets, but their tense forms tell her all she needs to about this enemy.

She sends her drone out in the middle of the battle and readies her shotgun. For a brief second, she wishes Kal'Reegar were here. She shakes it off and fires at the Praetorian, never relenting until it explodes in a bright blue and black mess of confetti.

* * *

His heart is pounding as he watches her wring her hands together, her voice shaky. Tali'Zorah stood against geth many times before. She only hid from the danger on Haestrom at Kal's insistence, and only when he reminded her of the mission. Now she stands against the Admiralty Board as they throw atrocious accusations at her. She is, Kal realizes, frightened.

Not that he blames her. The Migrant Fleet is everything. Death at the hands of geth is a much more welcome fate than exile. But Tali'Zorah is blessed with a charismatic and strong captain who is staying calm as she addresses the admirals, and Kal is thankful that Commander Shepard is here. She is Tali's best hope.

He still wishes he had more than guns and rocket launchers to use for her defense. But at that rate, both of them would be exiled.

He isn't sure if he will be willing to stay with the Fleet if they do not exonerate her, anyway.

When his suggestion to send Tali'Zorah to retake the Alarei remains in Admiral Raan's plans, Kal is relieved, and he wants nothing more to accompany her. But, orders. He knows that Tali will be fine with Shepard, and it is nothing they cannot handle, but he still sends the first real prayer in his life to the ancestors for her safe return.

* * *

They return from the Alarei, and the trial is already in progress. Tali prays and wishes that Shepard doesn't reveal the evidence they found. To lose her father twice in the same day would be absolutely unbearable, and if the alternative is exile, then so be it.

Shepard narrows her eyes and turns away from the Admiralty Board, shouting to the gathered witnesses about the injustice of the trial. Shala'Raan seems dismayed, and Zaal'Koris looks unconvinced, and Tali feels that her exile is inevitable despite Veetor's plea and the cowing of the quarians around her. She braces herself for judgment, and then her heart leaps at the sound of _his_ voice overpowering the crowd.

"Tali's done more for this Fleet than you assholes ever will! You're pissing on everything I fought for; everything Tali fought for! So if you exile her, you may as well do the same to me."

Tali glances over her shoulder and sees Kal'Reegar with clenched fists, leaning forward as though to stare the admiralty down. He put himself on the chopping block for her sake, Tali realizes. She can barely hear anything else over the sound of her own heart. Tali wonders what she has done to earn such a strong sentiment, and she wants to tell Kal to take it back. He should not let himself be exiled for her sake. But her mouth is dry and she cannot find words. As she turns back to the admirals, she is able to meet their eyes through the masks. She holds her breath, but now she is unafraid.

She is ready for her sentence.

When Tali is found innocent, the first person she seeks out is Kal. She is still in awe by his words, and she stumbles as she expresses her appreciation. Tali knows it is his reflexes that answer with, "You would have done the same for me."

There is a short silence, and Kal quickly, almost sheepishly, changes the subject. Tali realizes that he is not wrong.

As she and Shepard make a round through the plaza to thank Veetor for his part in the trial and to have one last chat with each admiral, Tali forces herself not to look over her shoulder at the marine who saved her from exile. But when the time comes to return to the Normandy, Tali stops short of exiting the plaza. Then she finally succumbs to the compulsion.

Kal is watching her. Tali is conflicted: the mask is letting her decide how to respond, if she wants to respond, but the mask is also keeping her from seeing his face and what he is feeling as she departs. She wants now more than ever to see another quarian's face, but she knows she must be content as he makes one short nod in farewell.

Tali nods back, and she pays no attention to the reignited fluttering in her chest. Euphoria, she decides, left over from the trial, and has nothing to do with how Kal knows she found evidence without her saying anything, how much Kal has learned about her research since escaping Haestrom, and how Kal is one of the three people who made sure she is walking out of here part of the Migrant Fleet.

* * *

It is another week and a half after Tali's trial when Kal is sent on another mission. It is a bigger team of engineers and scientists this time, and the ratio is one tech to one marine instead of an entire squad to one tech. They are not going back into geth space; at least, not yet. The techs keep to themselves, and so do the marines, and Kal finds he has little interest in engaging anyone in more conversation than necessary. He tries to eavesdrop on the techs' conversations about their theories and their findings, but now that he knows why he is curious, he does not tempt questions and curiosity by prying.

During the day, he keeps focused on his mission, refusing to let lingering thoughts distract him. At night, he is shameless, and he lies on his cot and wants to know what Tali is up to. What is she doing with Shepard, what enemy she is facing, and will she be alright?

But of course she will be fine, Kal tells himself.

His last thoughts before drifting into sleep are how he wishes he was with her, and how he hopes that he can see her again soon.

* * *

They are on their way to the Omega-4 Relay when Tali finally has some time to herself. Everyone knows that this is a suicide mission, but Shepard is insistent that they are to survive.

Tali's mind drifts. To her mother, who was always gentle and kind but with a mind to outmatch the top engineers in the Flotilla. To Shala'Raan, and how she manipulated Tali and the admirals before and during her trial. To her father, his heroism and his betrayal for the good of the Fleet, and his promise to build Tali a house on the homeworld, the promise that ultimately killed him.

She thinks of the powerful words Shepard shouted to the quarians at the trial, rousing them to their feet, and all the times she came through for her, saving her from Fist and helping with her Pilgrimage. Tali thinks of her banters with Garrus and how relieved she is that he is on this crazy mission, too. She remembers Engineer Adams and how kind he was to her, and just how much she misses him and wishes that he was here.

And, she thinks of Kal'Reegar and their time on Haestrom while the other marines slept, and the words he flung at the admirals on the Rayya, and deep down in her heart she believes that they cannot fail.


End file.
